\Sun"day\, n. [AS. sunnand[ae]g; sunne, gen. sunnan, the
sun + d[ae]g day; akin to D. zondag, G. sonntag; -- so called
because this day was anciently dedicated to the sun, or to
its worship. See {Sun}, and {Day}.]
The first day of the week, -- consecrated among Christians to
rest from secular employments, and to religious worship; the
Christian Sabbath; the Lord's Day.
{Advent Sunday}, {Low Sunday}, {Passion Sunday}, etc. See
under {Advent}, {Low}, etc.
Syn: See {Sabbath}.

\Sun"day\, a.
Belonging to the Christian Sabbath.
{Sunday letter}. See {Dominical letter}, under {Dominical}.
{Sunday school}. See under {School}.